Upon turning on ignition I'm not getting an engine management light.Sometimes it will start but will die out soon after starting.After dying out and ignition on there is a lot of relays clicking at the back of the engine around inlet manifold.Then will crank but will not fire.

Any ideas where to start?

I've checked the fuel pump by crossing terminals with ignition on and I can hear the fuel returning to tank.I've tried with a new battery but same result.

From reading his previous posts the they will need capacitor replacement at minimum and possibly repair to the PCB tracks as the electrolyte that leaks out of the blown capacitor eats the copper tracks.

Your best bet is to take the lid off, look for goop on the PBC/capacitors and take a close up pic and post it here.

The capacitors failing alone won't stop it working, so it will almost inevitably have eaten at least one track as well.

Repair is fairly simple to someone who knows what they're doing, normally about 1/2 hour to remove capacitors, clean up the mess with solvent, replace capacitors, solder links across any eaten tracks and spray with conformal coating.

Hmm, nichicon I thought were a decent capacitor, for some reason I thought Toyota used "suntan" brand?

I'm begining to suspect that high frequency ripple may be a factor. Certainly the one on the bottom board is decoupling for the flyback energy from the idle solenoid. Under these conditions I would normally use a ceramic e.g. 0.1uF in paralell to absorb the high frequency stuff as electrolytics arn't great for this.

It could, of course, still be a 'bad batch' as per my original thinking.